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Some more small improvements in response to 7.4 interactive docs comments.
This commit is contained in:
Tom Lane
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commit
b548cde1f5
@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.28 2005/01/05 14:22:39 petere Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.29 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -157,6 +157,20 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name
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</para>
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</refsect1>
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<refsect1>
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<title>Examples</title>
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<para>
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Create a new table <literal>films_recent</literal> consisting of only
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recent entries from the table <literal>films</literal>:
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<programlisting>
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CREATE TABLE films_recent AS
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SELECT * FROM films WHERE date_prod >= '2002-01-01';
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</programlisting>
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.21 2005/01/04 00:39:53 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.22 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -100,6 +100,33 @@ DELETE <replaceable class="parameter">count</replaceable>
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</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>
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<productname>PostgreSQL</productname> lets you reference columns of
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other tables in the <literal>WHERE</> condition. For example, to
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delete all films produced by a given producer, one might do
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<programlisting>
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DELETE FROM films
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WHERE producer_id = producers.id AND producers.name = 'foo';
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</programlisting>
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What is essentially happening here is a join between <structname>films</>
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and <structname>producers</>, with all successfully joined
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<structname>films</> rows being marked for deletion.
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This syntax is not standard. A more standard way to do it is
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<programlisting>
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DELETE FROM films
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WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');
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</programlisting>
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In some cases the join style is easier to write or faster to
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execute than the sub-select style. One objection to the join style
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is that there is no explicit list of what tables are being used,
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which makes the style somewhat error-prone; also it cannot handle
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self-joins.
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</para>
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</refsect1>
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<refsect1>
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<title>Examples</title>
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@ -122,7 +149,9 @@ DELETE FROM films;
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<title>Compatibility</title>
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<para>
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This command conforms to the SQL standard.
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This command conforms to the SQL standard, except that the ability to
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reference other tables in the <literal>WHERE</> clause is a
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<productname>PostgreSQL</productname> extension.
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</para>
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</refsect1>
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</refentry>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.9 2005/01/04 00:39:53 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.10 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -29,7 +29,7 @@ DROP GROUP <replaceable class="PARAMETER">name</replaceable>
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<para>
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<command>DROP GROUP</command> removes the specified group. The
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users in the group are not deleted.
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users in the group are not removed.
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</para>
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</refsect1>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/insert.sgml,v 1.28 2005/01/04 00:39:53 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/insert.sgml,v 1.29 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -162,7 +162,7 @@ INSERT INTO films VALUES
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</para>
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<para>
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In this second example, the <literal>len</literal> column is
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In this example, the <literal>len</literal> column is
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omitted and therefore it will have the default value:
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<programlisting>
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@ -172,7 +172,7 @@ INSERT INTO films (code, title, did, date_prod, kind)
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</para>
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<para>
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The third example uses the <literal>DEFAULT</literal> clause for
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This example uses the <literal>DEFAULT</literal> clause for
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the date columns rather than specifying a value:
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<programlisting>
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@ -184,11 +184,20 @@ INSERT INTO films (code, title, did, date_prod, kind)
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</para>
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<para>
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This example inserts several rows into table
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<literal>films</literal> from table <literal>tmp</literal>:
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To insert a row consisting entirely of default values:
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<programlisting>
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INSERT INTO films SELECT * FROM tmp;
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INSERT INTO films DEFAULT VALUES;
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</programlisting>
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</para>
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<para>
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This example inserts some rows into table
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<literal>films</literal> from a table <literal>tmp_films</literal>
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with the same column layout as <literal>films</literal>:
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<programlisting>
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INSERT INTO films SELECT * FROM tmp_films WHERE date_prod < '2004-05-07';
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</programlisting>
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</para>
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.32 2005/01/04 03:58:16 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.33 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -105,6 +105,19 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
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</para>
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</refsect1>
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<refsect1>
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<title>Examples</title>
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<para>
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Create a new table <literal>films_recent</literal> consisting of only
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recent entries from the table <literal>films</literal>:
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<programlisting>
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SELECT * INTO films_recent FROM films WHERE date_prod >= '2002-01-01';
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</programlisting>
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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@ -120,6 +133,14 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
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new code.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<simplelist type="inline">
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<member><xref linkend="sql-createtableas" endterm="sql-createtableas-title"></member>
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</simplelist>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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@ -1,5 +1,5 @@
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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.31 2005/01/04 03:58:16 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.32 2005/01/09 05:57:45 tgl Exp $
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PostgreSQL documentation
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-->
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@ -114,8 +114,9 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> SET <replacea
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expressions. This is similar to the list of tables that can be
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specified in the <xref linkend="sql-from"
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endterm="sql-from-title"> of a <command>SELECT</command>
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statement; for example, an alias for the table name can be
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specified.
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statement. Note that the target table must not appear in the
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<replaceable>fromlist</>, unless you intend a self-join (in which
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case it must appear with an alias in the <replaceable>fromlist</>).
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</para>
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</listitem>
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</varlistentry>
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@ -154,10 +155,13 @@ UPDATE <replaceable class="parameter">count</replaceable>
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<title>Notes</title>
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<para>
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When joining the target table to other tables using a <replaceable
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class="PARAMETER">fromlist</replaceable>, be careful that the join
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When a <literal>FROM</> clause is present, what essentially happens
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is that the target table is joined to the tables mentioned in the
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<replaceable>fromlist</replaceable>, and each output row of the join
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represents an update operation for the target table. When using
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<literal>FROM</> you should ensure that the join
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produces at most one output row for each row to be modified. In
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other words, a target row mustn't join to more than one row from
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other words, a target row shouldn't join to more than one row from
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the other table(s). If it does, then only one of the join rows
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will be used to update the target row, but which one will be used
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is not readily predictable.
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@ -210,15 +214,18 @@ UPDATE employees SET sales_count = sales_count + 1 WHERE id =
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</programlisting>
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Attempt to insert a new stock item along with the quantity of stock. If
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the item exists, update the stock count of the existing item. To do this,
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use savepoints.
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the item already exists, instead update the stock count of the existing
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item. To do this without failing the entire transaction, use savepoints.
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<programlisting>
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BEGIN;
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-- other operations
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SAVEPOINT sp1;
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INSERT INTO wines VALUES('Chateau Lafite 2003', '24');
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-- Check for unique violation on name
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-- Assume the above fails because of a unique key violation,
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-- so now we issue these commands:
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ROLLBACK TO sp1;
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UPDATE wines SET stock = stock + 24 WHERE winename = 'Chateau Lafite 2003';
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-- continue with other operations, and eventually
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COMMIT;
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</programlisting>
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</para>
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@ -228,10 +235,18 @@ COMMIT;
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<title>Compatibility</title>
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<para>
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This command conforms to the <acronym>SQL</acronym> standard. The
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<literal>FROM</literal> clause is a
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This command conforms to the <acronym>SQL</acronym> standard, except
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that the <literal>FROM</literal> clause is a
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<productname>PostgreSQL</productname> extension.
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</para>
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<para>
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Some other database systems offer a <literal>FROM</> option in which
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the target table is supposed to be listed again within <literal>FROM</>.
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That is not how <productname>PostgreSQL</productname> interprets
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<literal>FROM</>. Be careful when porting applications that use this
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extension.
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</para>
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</refsect1>
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</refentry>
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